Methods and Means for Measuring Multiple Casing Wall Thicknesses Using X-Ray Radiation in a Wellbore Environment

Abstract

An x-ray based cased wellbore simultaneous tubing and casing measurement tool is disclosed including at least an x-ray source; a radiation shield to define the output from of the produced x-rays; a two-dimensional per-pixel collimated imaging detector array; a secondary two-dimensional per-pixel collimated imaging detector array; a plurality of parallel hole collimators formatted such in one direction so as to form a pinhole in another direction; sonde-dependent electronics; and a plurality of tool logic electronics and PSUs. A method of using an x-ray based cased wellbore simultaneous tubing and casing measurement tool is also disclosed, the method including at least producing x-rays in a shaped output; measuring the intensity of backscatter x-rays returning from materials surrounding the wellbore; determining the inner and outer diameters of tubing and casing from the backscatter x-rays; and converting image data from said detectors into consolidated images of the tubing and casing.

Claims

1. An x-ray-based cased wellbore simultaneous tubing and casing measurement tool comprising a source collimator located cylindrically around an X-ray source with a plurality of collimated per-pixel collimated imaging detector arrays, wherein said collimators are formed as pinholes in the transverse direction and a parallel hole collimator sets in the axial direction, and said tool comprises; an x-ray source; a radiation shield to define the output from of the produced x-rays; a two-dimensional per-pixel collimated imaging detector array; a secondary two-dimensional per-pixel collimated imaging detector array; a plurality of parallel hole collimators formatted such in one direction so as to form a pinhole in another direction; sonde-dependent electronics; and a plurality of tool logic electronics and PSUs.

2. The tool of claim 1, wherein said imaging detector further comprises two-dimensional per-pixel collimated imaging detector arrays wherein the imaging array is one pixel wide and multiple pixels long.

3. The tool of claim 1, wherein said imaging detectors comprise two sets of two-dimensional per-pixel collimated imaging detector arrays.

4. The tool of claim 1, wherein said imaging detectors comprise a plurality of two-dimensional per-pixel collimated imaging detector arrays.

5. The tool of claim 1; wherein said imaging detectors comprise a plurality of collimated scintillator-based detector arrays.

6. The tool of claim 1, wherein the images contain spectral information to inform the characteristics of any wellbore materials or debris.

7. The tool of claim 1, wherein said shield further comprises tungsten.

8. The tool of claim 1, wherein the tool is configured so as to permit through-wiring.

9. The tool in claim 1, wherein the tool would be combinable would other measurement tools comprising one or more of acoustic or ultrasonic.

10. The tool in claim 1, wherein the tool would be used to determine the inner diameter of a tubing or casing.

11. The tool in claim 1, wherein the tool would be used to determine the outer diameter of a tubing or casing.

12. The tool in claim 1, wherein the tool would be used to determine the distribution and inner diameter of a scale upon the inner diameter of tubing or casing.

13. The tool in claim 1, wherein the tool would be used to determine the position, distribution and area of perforations, within the casings surrounding the cased wellbore.

14. The tool in claim 1, wherein the tool would be used to determine the position and integrity sand-screens, within the casings surrounding the cased wellbore.

15. The tool in claim 1, wherein the tool would be used to determine the position and integrity of gravel-packs, within the casings surrounding the cased wellbore.

16. The tool in claim 1, wherein the tool would be used to determine the position and integrity of side-pocket mandrels, within the casings surrounding the cased wellbore.

17. The tool in claim 1, wherein machine learning is employed to automatically reformat or re-tesselate the resulting images as a function of depth and varying logging speeds or logging steps.

18. A method of using an x-ray-based cased wellbore simultaneous tubing and casing measurement tool comprising a source collimator located cylindrically around an X-ray source with a plurality of collimated per-pixel collimated imaging detector arrays wherein said collimators are formed as pinholes in the transverse direction and a parallel hole collimator sets in the axial direction, said method comprising: producing x-rays in a shaped output; measuring the intensity of backscatter x-rays returning from materials surrounding the wellbore; determining the inner and outer diameters of tubing and casing from the backscatter x-rays; and converting image data from said detectors into consolidated images of the tubing and casing.

19. The method of claim 18, wherein said imaging detector comprises a two-dimensional per-pixel collimated imaging detector arrays wherein the imaging array is one pixel wide and multiple pixels long.

20. The method of claim 18, wherein said imaging detectors comprise a two sets of two-dimensional per-pixel collimated imaging detector arrays.

21. The method of claim 18, wherein said imaging detectors comprise a plurality of two-dimensional per-pixel collimated imaging detector arrays.

22. The method of claim 18, wherein the images contain spectral information to inform the characteristics of any wellbore materials or debris.

23. The method of claim 18, wherein the tool is combinable would other measurement methods comprising one or more of acoustic or ultrasonic.

24. The method of claim 18, wherein the tool would be used to determine the inner diameter of tubing or casing.

25. The method of claim 18, wherein the tool is used to determine the outer diameter of a tubing or casing.

26. The method of claim 18, wherein the tool is used to determine the distribution and inner diameter of a scale upon the inner diameter of a tubing or casing.

27. The method of claim 18, wherein the tool is used to determine the position, distribution and area of perforations within the casings surrounding the cased wellbore.

28. The method of claim 18, wherein the tool would be used to determine the position and integrity of sand-screens, within the casings surrounding the cased wellbore.

29. The method of claim 18, wherein the tool would be used to determine the position and integrity of gravel-packs within the casings surrounding the cased wellbore.

30. The method of claim 18, wherein the tool is used to determine the position and integrity of side-socket mandrels, within the casings surrounding the cased wellbore.

31. The method of claim 18, wherein machine learning is employed to automatically reformat or re-tesselate the resulting images, as a function of depth and varying logging speeds or logging steps.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 illustrates an x-ray-based tubing and casing measurement tool being deployed into a borehole via wireline conveyance. Regions of interest within the materials surrounding the borehole are also indicated.

[0026] FIG. 2 illustrates an example embodiment of an x-ray-based tubing and casing measurement tool arranged so as to enable imaging of the inner-most casing or tubing and outer casing.

[0027] FIG. 3 illustrates an example embodiment of an x-ray-based tubing and casing measurement tool, arranged such as to enable imaging of the inner-most casing or tubing and 10 outer casing. The figure illustrates how an arrangement of scintillators coupled to photomultiplier tubes or photodiodes may be used to determine the thickness of the outer casing.

BRIEF DESCRIPTION OF SEVERAL EXAMPLE EMBODIMENTS

[0028] The example methods and means disclosed herein for determining casing and tubing integrity while simultaneously performing casing integrity evaluations located immediately surrounding the borehole through x-ray backscatter imaging in a cased wellbore environment, is embodied in a package configured so as to not require direct physical contact with the well casings (i.e., non-padded). The methods and means disclosed herein further employ a combination of collimators located cylindrically around an X-ray source, located within a non-padded concentrically-located borehole logging tool, together with axially offset arrangements of a plurality of fixed three-dimensional hybrid collimated imaging detector array(s) to also be used as the primary imaging detector(s). The capability of control the solid angle of the collimated source permits the operator to either log the tool through the well casing while the detectors measure the inner diameter and outer diameter of tubing or casing, and/or to produce a fully azimuthal two dimensional backscatter x-ray image, or to hold the tool stationary as the collimated detectors image azimuthally to capture a cylindrical image that can be improved upon ‘statically’ (as the detector continues to recapture casing images that can be added to the existing image set).

[0029] With reference now to the attached drawings, FIG. 1 illustrates an example embodiment an x-ray-based tubing imaging tool [101] is deployed by wireline conveyance [104] into a tubing [102] within a cased [103] borehole, wherein the tubing [102] is imaged simultaneously with the well casing [103] that is cemented into the formation [105]. The tool is enclosed by a pressure housing [201] which ensures that well fluids are maintained outside of the housing.

[0030] FIG. 2 illustrates pressure housing [201] conveyed through a well tubing [202]. The pressure housing contains an electronic x-ray source [203] which is configured to produce x-rays panoramically in a conical output [212]. The conical x-ray beam [212] illuminates a cylindrical section of the tubing [202], the annular fluids outside of the tubing [205], the next casing [206], and the surrounding cement [207]. The radiation scattering from the tubing is imaged by a near-field group of azimuthally arranged plurality of two-dimensional detector arrays [208], which are collocated with three-dimensional parallel hole collimators [209]. The detector collimators [209] reduce the field of view of each pixel of the detector array such that each pixel images a distinct and unique section, of the illuminated tubing [202]. The radiation scattering from the casing [206] is imaged by a far-field group of azimuthally arranged plurality of two-dimensional detector arrays [210], which are collocated with three-dimensional parallel hole collimators [211]. The detector collimators reduce the field of view of each pixel of the detector array such that each pixel images a distinct and unique section of the illuminated casing [206]. The collimators are formed such that, in the transverse direction, they thin′ the geometry of a typical pinhole detector, however, in the axial-radial direction they form the geometry of a plurality of parallel hole collimators. The tool is then arranged such that the narrow conical beam [212] intersects the tubing or casing and can be used to measure the thickness of the tubing or casing precisely. As the axial offset for each pixel is known, along with the angle and field-of-view of the collimator and the angle and divergence of the beam, each pixel can be easily remapped to a radially positioned voxel along the beam-path.

[0031] In a further embodiment, the tool is arranged such that, the narrow conical beam intersects the tubing or casing and is used to measure the thickness of the tubing or casing precisely, in addition to the thickness of scale deposits on the inner-diameter of the tubing/casing. As the axial offset for each pixel is known, along with the angle and field-of-view of the collimator and the angle and divergence of the beam, each pixel is easily remapped to a radially positioned voxel along the beam-path.

[0032] In another embodiment, a pressure housing [301] is conveyed through a well tubing [302]. The pressure housing contains an electronic x-ray source [303] configured to produce x-rays panoramically in a conical output [314]. The conical x-ray beam [314] illuminates a cylindrical section of the tubing [302], the annular fluids outside of the tubing [305], the next casing [306], and the surrounding cement [307]. The radiation scattering from the tubing is imaged by a near-field group of azimuthally arranged plurality of two-dimensional detector arrays [308], which are collocated with three-dimensional parallel hole collimators [309]. The detector collimators reduce the field of view of each pixel of the detector array such that each pixel images a distinct and unique section of the illuminated tubing [302]. The radiation scattering from the casing [306] is imaged by a far-field group of an azimuthally arranged plurality of scintillator crystals attached to photo-multiplier tubes and/or photodiodes [310], that are collimated [311] such that each axially offset detector receives scattered radiation from a similar region to the other detectors on a similar azimuthal, plane. This approach allows multiple views of the same annular fluid volume [305] such that the density and thickness of the annular volume can be computed from the received counts (in each detector) and the casing thickness can be inferred from the subtraction of radial thickness of the fluid from the known outer dimension of the casing. A further long-space′ detector [313] is collimated [312] such that the received scattered photons emanate from the casing and cement interface region, such that any variation in response not noted by the annular fluid detector group would be the result of variations in the outer-diameter of the casing.

[0033] In a further embodiment, the axial length of the imaging detector group is increased such that an additional casing, such as a second casing outside of the initial tubing and first casing, can be interrogated for the purposes of measuring the inner and outer diameters of the metal volume.

[0034] In a further embodiment, an additional imaging detector group is added with a larger axial offset from the source, such that an additional casing, such as a second casing outside of the initial tubing and first casing, can be interrogated for the purposes of measuring the inner and outer diameters of the metal volume.

[0035] In a further embodiment, additional imaging detector groups are added with a larger axial offsets from the source, such that multiple additional casings are interrogated for the purposes of measuring the inner and outer diameters of the metal volumes.

[0036] In another embodiment, as the tool is logged axially, each axial ‘column’ of pixels of the detector arrays is sampled such that each column would image a similar section of the casing/tubing that had been imaged by its neighbor prior during the last sample. Upon encoding the images with the known azimuthal capture position of the image section, the separate image pixel columns associated with each imaged ‘slit’ section of the casing/tubing can be summated/averaged to produce a higher quality image within a single pass.

[0037] In a further embodiment, the operator stops the conveyance of the tool and uses the azimuthal imaging detector assembly to continually sample the same images tubing/casing illuminated cylinder section, such that the resulting data set can build/summate statistically to improve image quality.

[0038] In another embodiment, the backscatter images also contains spectral infatuation, such that a photo-electric or characteristic-energy measurement may be taken, such that the imaged material is analyzed for scale-buildup or casing corrosion.

[0039] In a further embodiment, machine learning is employed to automatically analyze the spectral (photo electric or characteristic energy) content of the images to identify key features, such as corrosion, holes, cracks, scratches, and/or scale-buildup.

[0040] In a further embodiment, the per-pixel collimated imaging detector array is a single ‘strip’ array, i.e., one pixel wide azimuthally, and multiple pixels long axially—the imaging result is a ‘cylindrical’ ribbon image. The tool is then moved axially (either by wireline-winch or with a stroker) and a new image set taken, such that a section of casing could be imaged by stacking cylindrical ribbon images/logs.

[0041] In a further embodiment, machine learning is employed to automatically reformat (or re-tesselate) the resulting images as a function of depth and varying logging speeds or logging steps, such that the finalized casing and/or cement image is accurately correlated for azimuthal direction and axial depth by comparing with CCL, wireline run-in measurements, and/or other pressure/depth data.

[0042] The foregoing specification is provided only for illustrative purposes, and is not intended to describe all possible aspects of the present invention. While the invention has herein been shown and described in detail with respect to several exemplary embodiments, those of ordinary skill in the art will appreciate that minor changes to the description, and various other modification, omissions and additions may also be made without departing from the spirit or scope thereof.